RECOVERING H2 AND C2+ HYDROCARBONS FROM FUEL GAS VIA USE OF A TWO-STAGE PSA PROCESS AND SENDING PSA TAIL GAS TO A GAS RECOVERY UNIT TO IMPROVE STEAM CRACKER FEED QUALITY
The invention provides a process for treating a gas stream comprising hydrogen, methane and C2+ hydrocarbons comprising sending the gas stream to a pressure swing adsorption unit to produce a first purified gas stream comprising hydrogen and methane and a second purified gas stream comprising hydrogen, methane and C2+ hydrocarbons, sending the first purified gas stream to a second pressure swing adsorption unit to produce a hydrogen product stream comprising more than 99 mol % hydrogen and a fuel gas stream comprising more than 90 mol % of the methane in the first product gas stream, and sending the second purified gas stream to a gas plant to be separated into a plurality of streams.
This application claims priority from Provisional Application No. 62/017,827 filed Jun. 26, 2014, the contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTIONThe invention provides a process for treating gases containing hydrogen, methane and C2+ hydrocarbons to recover hydrogen gas to produce a pure hydrogen stream, methane to be used as fuel gas or other application and C2+ hydrocarbons to be sent to a steam cracker.
SUMMARY OF THE INVENTIONThe invention provides a process for treating a gas stream comprising hydrogen, methane and C2+ hydrocarbons comprising sending the gas stream to a pressure swing adsorption unit in order to produce a first purified gas stream comprising hydrogen and methane and a second purified gas stream comprising hydrogen, methane and C2+ hydrocarbons, sending the first purified gas stream to a second pressure swing adsorption unit to produce a hydrogen product stream comprising more than 99 mol % hydrogen and a fuel gas stream comprising more than 90 mol % of the methane in the first product gas stream, and sending the second purified gas stream to a gas recovery unit (“gas plant”) to be separated into a plurality of streams.
An example base scheme for a gas processing section within an integrated refinery and steam cracker complex is shown in
The following assessment is based on the diagram in
Without further elaboration, it is believed that using the preceding description that one skilled in the art can utilize the present invention to its fullest extent and easily ascertain the essential characteristics of this invention, without departing from the spirit and scope thereof, to make various changes and modifications of the invention and to adapt it to various usages and conditions. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limiting the remainder of the disclosure in any way whatsoever, and that it is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.
In the foregoing, all temperatures are set forth in degrees Celsius and, all parts and percentages are by weight, unless otherwise indicated.
SPECIFIC EMBODIMENTSWhile the following is described in conjunction with specific embodiments, it will be understood that this description is intended to illustrate and not limit the scope of the preceding description and the appended claims.
A first embodiment of the invention is a process for treating a gas stream comprising hydrogen, methane and C2+ hydrocarbons comprising sending the gas stream to a pressure swing adsorption unit to produce a first purified gas stream comprising hydrogen and methane and a second purified gas stream comprising hydrogen, methane and C2+ hydrocarbons, sending the first purified gas stream to a second pressure swing adsorption unit to produce a hydrogen product stream comprising more than 99 mol % hydrogen and a fuel gas stream comprising more than 90 mol % of the methane in the first purified gas stream, and sending the second purified gas stream to a gas plant to be separated into a plurality of streams. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the plurality of streams comprises a lean gas stream, a C3 hydrocarbons stream, a C4 hydrocarbons stream, a rich oil stream and a naphtha stream comprising C5+ hydrocarbons. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the lean gas stream, the C3 hydrocarbons stream, the C4 hydrocarbons stream, the rich oil stream, and the naphtha stream are sent to a steam cracker. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the fuel gas stream comprises about 55 mol % hydrogen, 45 mol % C1 and 0.3 mol % C2+ hydrocarbons. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the lean gas stream is sent to a third pressure swing adsorption unit to produce a tail gas stream comprising C2+ hydrocarbons and a hydrogen/methane stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the hydrogen/methane stream is sent to a fourth pressure swing adsorption unit to produce an additional hydrogen stream comprising more than 99 mol % hydrogen and an additional fuel gas stream comprising hydrogen and methane.
Without further elaboration, it is believed that using the preceding description that one skilled in the art can utilize the present invention to its fullest extent and easily ascertain the essential characteristics of this invention, without departing from the spirit and scope thereof, to make various changes and modifications of the invention and to adapt it to various usages and conditions. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limiting the remainder of the disclosure in any way whatsoever, and that it is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.
In the foregoing, all temperatures are set forth in degrees Celsius and, all parts and percentages are by weight, unless otherwise indicated.
Claims
1. A process for treating a gas stream comprising hydrogen, methane and C2+ hydrocarbons comprising sending said gas stream to a pressure swing adsorption unit to produce a first purified gas stream comprising hydrogen and methane and a second purified gas stream comprising hydrogen, methane and C2+ hydrocarbons, sending said first purified gas stream to a second pressure swing adsorption unit to produce a hydrogen product stream comprising more than 99 mol % hydrogen and a fuel gas stream comprising more than 90 mol % of said methane in said first purified gas stream, and sending said second purified gas stream to a gas plant to be separated into a plurality of streams.
2. The process of claim 1 wherein said plurality of streams comprises a lean gas stream, a C3 hydrocarbons stream, a C4 hydrocarbons stream, a rich oil stream and a naphtha stream comprising C5+ hydrocarbons.
3. The process of claim 2 wherein said lean gas stream, said C3 hydrocarbons stream, said C4 hydrocarbons stream, said rich oil stream, and said naphtha stream are sent to a steam cracker.
4. The process of claim 1 wherein said fuel gas stream comprises about 55 mol % hydrogen, 45 mol % C1 and 0.3 mol % C2+ hydrocarbons.
5. The process of claim 2 wherein said lean gas stream is sent to a third pressure swing adsorption unit to produce a tail gas stream comprising C2+ hydrocarbons and a hydrogen/methane stream.
6. The process of claim 5 wherein said hydrogen/methane stream is sent to a fourth pressure swing adsorption unit to produce an additional hydrogen stream comprising more than 99 mol % hydrogen and an additional fuel gas stream comprising hydrogen and methane.
Type: Application
Filed: Jun 18, 2015
Publication Date: Dec 31, 2015
Inventors: Robert E. Tsai (Arlington Heights, IL), Xin X. Zhu (Long Grove, IL), Ronald J. Long (Arlington Heights, IL)
Application Number: 14/743,407